Script to use IPTables to prevent outbound traffic when using network taps and monitoring network traffic.

iptables_monitor.sh

#!/bin/bash
ipt4='/sbin/iptables'
ipt6='/sbin/ip6tables'

for i in $ipt4 $ipt6; do
    # Flush Rules
    echo 'Flushing IPTables: ' $i
    $i -F
    $i -X

    # If there is a parameter, then disable outbound
    if test $# -gt 0; then
	      if [[ "$1" == "start" ]]; then
	          # Block Rules
		        echo 'Blocking outbound traffic'
            $i -A OUTPUT -j DROP
	      fi
	  fi
done